Keane, Niamh

7094 Background: Obesity is associated with comorbidities that could cause negative outcome upon delivering intensive care. In pediatric AML patients (pts), obesity was associated with more toxicity and worse prognosis. Here, we study Body-Mass Index (BMI) impact on clinical outcome of adult AML pts. Methods: A total of 180 adult pts with AML between 2003-2011 were enrolled. Retrospective data included demographics, labs, cytogenetics and outcome. LeukemiaNET Standardization (LNS), complete remission (CR), overall survival (OS) and relapse free survival (RFS) were obtained (Dohner E, Blood 2010). BMI of 25-30 was defined as overweight, while >30 as obesity. Fischer’s and Wilcoxon tests were used for comparatives between groups, cox proportional hazards and logistic regression for associations for OS/RFS and CR, Kaplan-Meier test for OS and RFS estimates via JMP software V9.0. IRB approval was obtained according to Helsinki declaration. Results: The median age was 63 years, with 115 (64%) were men. Of 159 pts, karyotype was favorable, Intermediate I, II and adverse in 21 (13%), 76 (48%), 23 (%14) and 39 (25%) pts respectively. Median BMI was 28.2 (range 16.8-47.8). 48 (26%) had normal BMI, 62 (34%) were overweight, and 70 (38%) were obese. At diagnosis, BMI classes were not associated with age, sex, glucose, white blood count (WBC), platelets, blasts, ECOG status, LNS, FLT3/NPM1 status; nor treatment toxicities, CR rates, or relapse after CR. BMI classes were associated with presence of concomitant comorbidities (p=0.047) and glucose levels (p=0.044). In univariate analysis, overweight (OR=1.8, p=0.16) and obesity (OR=1.9, p=0.13) did not affect CR rates. On adjusting for age, sex, LNS, WBC and blast count at diagnosis, only overweight pts had a significant higher CR (76% vs 63%) rates (OR=2.99, p=0.043). OS and RFS were not associated with BMI in univariate (p=0.51) and multivariate (p=0.32) models. Median OS and RFS were not different across BMI subgroups (p=0.52 and 0.59). Conclusions: BMI subgroups showed no correlation with treatment toxicity, LNS, relapse rates, OS or RFS. This should encourage giving therapy to pts regardless of their BMI status. Overweight was associated with better CR rates despite increased concomitant morbidities.

Abstract MYC expression is frequently dysregulated in multiple myeloma (MM). In one comprehensive study, MYC structural variations (SV) were found in nearly half of MM cases (Affer et al. Leukemia 2014). The prevalence was higher in hyperdiploid (HRD) tumors (65%) compared to non-hyperdiploid (NHRD) tumors (36%). The large amount of tumor DNA required for all of the genomic studies performed may have biased the samples analyzed (e.g., to those with higher tumor burdens). To validate the findings of recurrent MYC SV in another dataset, we analyzed the CoMMpass data. We analyzed long-insert whole genome sequencing (WGS) data from diagnostic samples in 420 patients from the IA7 release (dbGAP phs000748) for SV. The results of clinical data, processed WES (SNV), RNASeq (gene expression) and WGS (copy number) data from IA8 (http://research.themmrf.org) were used to calculate survival, RAS and NFKB pathway mutation (WES), TC class (RNA), NFKB index (RNA) and hyperdiploid index (WGS). MYC SVs were identified in 38% of tumors. They were present in 53% HRD and 28% NHRD, and by TC in 55% D1, 43% D2, 36% MMSET, 26% MAF, 13% CCND. Juxtaposition of an Ig enhancer (IgH, IgK, IgL) close to MYC was the most common MYC SV, representing ~40% of the MYC SV. Other enhancers identified have mostly been reported previously, with the most frequent being NSMCE2 (12% of SV) and TXNDC5 (5% of SV). Intrachromosomal SV (deletions, inversions, duplications) not associated with any known enhancer were also frequent (18% of SV). As expected, MYC expression was higher in tumors with MYC SV compared to those without (~2.4 fold, p-value<0.0001). We used Gene Set Enrichment Analysis (GSEA) to identify activated pathways that might substitute for MYC in HRD patients without MYC SV and observed significant activation of the NFkB pathway. Interestingly, examining patients with RAS/MAPK pathway (NRAS, KRAS, BRAF, FGFR3 - abbreviated RAS) mutations (identified in 50% of all patients) the same pattern was observed: in the absence of RAS mutation, there was a significantly higher NFkB index. In general, the HRD tumors seem to have either activation of RAS and/or MYC, or activation of NFkB (Figure). There was no difference in overall survival in patients with versus those without MYC SV. We developed a clinically applicable sequencing platform to identify MYC SV, which cannot be reliably identified by FISH. We sought to validate this targeted capture approach, where in addition to the coding exons of 81 interesting genes described previously (M3P), we also pulled down the region surrounding MYC (2 Mb), IgH (0.5 Mb), IgK (50 kb) and IgL (100 kb) allowing us to additionally identify SV in MYC and Ig loci. Using this approach we identified IgH translocations in 29/30 samples with translocations previously identified by FISH (97%). Moreover, we identified MYC SV in 19/22 patients with SV previously identified by mate-pair WGS (86%). Importantly, sequencing identified the precise translocation breakpoint, and identity of the enhancer dysregulating MYC, which may be important variables. In one informative patient two different MYC SV were present at diagnosis, only one of which was still present following a partial response to four cycles of lenalidomide and dexamethasone. This suggests that the two MYC SV are in different subclones, one of which was much more sensitive to the treatment. Interestingly, the enhancer dysregulating MYC in the sensitive subclone harbors 5 strong Ikaros binding sites identified by ChIPseq, suggesting one intriguing mechanism for sensitivity to lenalidomide. To summarize, we verified in a large dataset that MYC expression is frequently dysregulated by SV in MM (38%), and the RAS/MAPK (50%) and NFKB (23%) pathways are frequently activated by mutations. Surprisingly, given their generally good prognosis, nearly half of HRD tumors seem to be MYC driven, while this is true for only a quarter of NHRD tumors. HRD tumors not driven by MYC or RAS appear to be driven by NFKB. Remarkably, the pathways most commonly activated by mutation in MM: CCND, MYC, RAS, NFKB are common to many cancers and have been studied extensively individually. To understand their clinical impact in MM we have developed a comprehensive custom capture sequencing panel that identified 97% of IgH translocations, 86% of MYC SV, and as well as SNV and CNV of 81 recurrently mutated genes. It will be important to include such a comprehensive genetic analysis to complement clinical trials in the future. Figure. Figure. Disclosures Stewart: Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Takeda Oncology: Consultancy; Janssen Pharmaceuticals: Consultancy.

Abstract Abstract 2525 Background: Patients with relapsed AML have a very poor outcome. The molecular signature at diagnosis has emerged as a significant marker for prognostic, and possibly therapeutic, values in newly-diagnosed AML. FLT3 mutations are found in about 25–30% of AML pts. In the absence of FDA-approved agents for FLT3, the prognostic value of FLT3 mutation on clinical outcome for relapsed AML (rAML) is not well documented. Aim: To study clinical implications of FLT3 status on rAML. Methods: All adult pts with AML diagnosed and treated at Mayo Clinic between 2003–2011were studied. Retrospective data collection included pts' demographics, laboratory tests, bone marrow biopsies, FLT3 mutation (internal tandem duplication (ITD) and tyrosine kinase domain (TKD) mutation), and survival information. IRB approval was obtained in accordance with Helsinki declaration. Chi-Square and T-test were used for comparatives between groups and Kaplan-Meier test was applied for survival estimates using JMP 9.0 software. Results: A total of 192 pts with newly-diagnosed with AML were identified. Sixty percent (115) were males, 88% (168) were Caucasians, 26% (49) had antecedent hematological disease (AHD), and 13% (25) had previous exposure to chemo- or radiotherapy. Forty-seven percent had a normal chromosomal analysis, and 18% (35) had FLT3 mutation (28 ITD, 7 TKD). In FLT3-mutated pts, median WBC was 70 x109/L (p=0.0016), hemoglobin 9.5 g /dL, and platelets 48 x109/L, compared to 8.8 x109/L, 9.1 g/dL, 50 x109/L in the rest of pts, respectively. Peripheral blood blasts were elevated in FLT3-mutated group compared to rest of pts (p 0.0059). A total of 128 pts achieved complete remission (CR), with 79 (62%) subsequently relapsed. Of the relapsed patients, 93% (74) were Caucasians, 54% (43) males, 22% (17) had AHD, and 8% (6) had prior chemo- or radiotherapy. Cytogenetics were diploid in 49% (39) and complex in 15% (12). Hematopoietic stem cell transplantation was performed in 30% (24) of pts. Eleven of 79 (14%) pts were FLT3-mutated at relapse (Group 1); with 1 pt having TKD-mutation. Forty-eight percent (38) of pts had unmutated-FLT3 (Group 2), and 38% (30) pts were FLT3-unknown (Group 3). In group 1, median WBC was 9.9 x109/L, hemoglobin 10.55 g /dL, platelets 55 x109/L, compared to 3.2 x109/L (p=0.0034), 10.55 g/dL, and 58 x109/L in group 2, respectively. Peripheral blasts were significantly elevated in group 1 compared to group 2 (38% vs 4%, p <0.0001). Surprisingly, 3/11 pts (27%) with FLT3 mutation at relapse were unmutated at diagnosis. CR was achieved in 2/11 (18%) pts in group 1 compared to 15/38 (39%) in group 2 (p=0.19). Median overall survival in rAML was significantly lower in group 1 compared to group 2 (90 days vs 229 days, p 0.0076). This survival difference was statistically more significant in pts with diploid cytogenetics at relapse compared to the rest (p 0.0009 vs 0.48, respectively). Within 1.5 years, all pts in group 1 died, compared to 21% survived in group 2. Conclusion: FLT3-mutated AML pts had a significantly higher peripheral WBC and blasts at both diagnosis and relapse. Importantly, FLT3 at relapse was found to be mutated in one quarter of pts who were wild-type FLT3 at diagnosis; raising the importance of assessing FLT3 gene on all relapses. FLT3 mutation significantly predicted worse median overall survival in rAML raising the need for novel agents, such as FLT3 inhibitors, in this population. Disclosures: No relevant conflicts of interest to declare.

Abstract Background Cytogenetic abnormalities have significant prognostic role in AML at the time of diagnosis. Several prognostic groupings have been recommended including the NCCN and European LeukemiaNet classification. It is still unknown whether cytogenetic abnormalities have any prognostic role at the time of relapse for predicting clinical outcome. In addition, clonal evolution (CE) has been seen in many AML cases, but its prognostic value remains to be identified. Aim To study cytogenetic abnormalities and clonal evolution impact on clinical outcome for patients diagnosed with rAML Method A retrospective, single institution study through chart review of all cases diagnosed with rAML at Mayo Clinic Rochester between 2003 to 2011 was performed. Pts who achieved complete remission and relapsed at our institution were included. Pts with PML-RARA and BCR-ABL rearrangements were excluded from this study. Pts with available cytogenetics data, both at presentation and relapse, were included. Response to treatment was defined as per international working group (IWG) criteria (Cheson JCO 2003). Appropriate IRB approval was obtained in accordance with Helsinki declaration. Comparison between groups’ medians was done using Wilcoxon test, while survival estimates were calculated using Kaplan-Meier curves using JMP V9. Results Out of 192 pts, 74 pts matched our inclusion criteria. The median age at diagnosis is 60 years (range 18-81), 53% were males. At relapse, median white blood cell (WBC) was 3.2 x109, hemoglobin 10.4 g/dL, platelet 59 x109, peripheral blood (PB) blast 2% (range, 0-96), bone marrow (BM) blasts 23% (range, 1-95) and cellularity 60%. Relapse site was mainly in the BM (95%). Flt3 mutation was found in 12/43 (28%), while NPM1 mutation in 2/7 (29%). Upon treatment with salvage therapy, 27 (36%) pts achieved complete remission (CR) and 16 (22%) pts partial remission (PR) for a total overall response (OR) of 58%. Twenty one (28%) pts were able to proceed to allogeneic stem cell transplant (SCT) after achieving remission. Median overall survival (mOS) was 198 days. Pts had a longer mOS if they proceeded to SCT (386 days vs 121 days, p =0.0003). Cytogenetic analysis (CG) were diploid in 32 (43%) of 74 pts at relapse. Five pts had favorable cytogenetics (3 pts with t(8,21) and 2 pts with inv (16)). CG was divided into favorable, intermediate and poor prognosis as per NCCN classification in 5 (7%), 45 (61%), 24 (32%), respectively. As per European LeukemiaNet, there were 4 CG groups divided into: favorable, Intermediate-1, intermediate-2, and adverse in 5 (7%), 33 (45%), 12 (16%), 24 (32%), respectively. Upon comparison of CG at diagnosis and relapse; clonal evolution (a change in CG due to gain or loss of chromosomal abnormalities) was found in 42/74 (57%) of pts. CG reverted back to diploid in 8/42 (19%) or gained additional CG abnormalities at relapse in 32 (76%) pts. CR2 was achieved in 80% of favorable CG (NCCN grouping), 40% (intermediate), and 21% in poor risk (p=0.01). Using NCCN CG grouping mOS was: 435 days (favorable), 266 (intermediate), and 104 (poor) (p value = 0.01). However, using European LeukemiaNet grouping mOS was: 435 days (favorable), 174 (intermeidtae-1), 363 (intermediate-2), and 104 (poor) (p=0.004). CE did not affect mOS (p =0.7). On multivariate analysis, response to salvage therapy (p<0.0001), NCCN CG grouping (p =0.03), wbc (p=0.045), and PB blasts (p=0.01) were significant but not age, BM blast, platelet and CE. Conclusion CG were diploid in 43% of relapsed pts. CE (gain or loss of cytogenetic abnormalities) was seen in 57% of CG at relapse compared to diagnosis but did not affect mOS. NCCN (and not European LeukemiaNet) cytogenetic grouping did affect clinical outcome through both achieving second CR and mOS (both on univariate and multivariate analysis). Our results confirm the prognostic value of CG on relapse, and need to be confirmed by larger studies. Disclosures: No relevant conflicts of interest to declare.

Abstract MYC dysregulation, the most common genetic aberration in multiple myeloma, is frequently due to the translocation of super-enhancers to the MYC locus. Several drugs target proteins that are enriched at many of these enhancers including BRD4 (BET inhibitors, BETi) and Ikaros (IMiDs), although their mechanism of action remains poorly understood. Here we present a characterization of the responses to these drugs in a collection of over sixty myeloma cell lines having a diversity of MYC rearrangements. We found that the anti-proliferative effects of these drugs significantly correlated with changes in MYC protein levels, consistent with both drugs targeting MYC expression. Despite this common target, there was no statistically significant correlation between the individual BETi and IMiD responses, suggesting that they act through different mechanisms. Of those lines having extremes of sensitivity or resistance, there were two major groups (BETiS/IMiDS and BETiS/IMiDR), a smaller group of four lines resistant to both drugs individually (BETiR/IMiDR) and only one line was BETiR/IMiDS. In the BETiR/IMiDR group, resistance to BETi was mediated by a BRD4-independent mechanism as BRD4 was efficiently released from the MYC-associated enhancers. In all three of BETiR/IMiDR cell lines that we examined, treatment with BETi and IMiD together abolished proliferation and down-regulated MYC, consistent with parallel BRD4- and Ikaros-dependent pathways driving MYC expression. These resistant lines all expressed high levels of the transcription factor ETV4 and knocking out its gene sensitized a line to each drug individually. Thus ETV4 appears to be necessary for the parallel pathways driving MYC expression. There were nine lines in the BETiS/IMiDR group. Sensitivity to BETi in these lines could be explained by either low ETV4 expression or by BETi repressing Ikaros levels (which was only observed in BETiS lines, suggesting that BRD4 drives IKZF1 expression in these lines). Thus, in ETV4-containing lines, BETi sensitivity is due to the simultaneously targeting of the BRD4- and Ikaros-dependent pathways. IMiD resistance likely was due to several reasons. In one cell line, OCIMY5, IMiD had little effect on Ikaros levels, likely due to the previously reported low levels of Cereblon. Seven of the eight remaining lines expressed high levels of either ETV4, or the other potential super-enhancer binding factors IRF4 or RUNX1. In the eight BETiS/IMiDS cell lines, IMiD strongly reduced both Ikaros and Aiolos protein levels, which likely caused IMiD sensitivity. As with the BETiS lines described above, the lines in this group either lacked ETV4 or BETi repressed Ikaros levels. In conclusion, by examining drug response in a collection of genetically annotated myeloma cell lines we have been able to identify factors that contribute the broad range of responses to BETi and IMiDs in myeloma cells. Citation Format: Daniel L. Riggs, Camille Herzog, Victoria M. Garbitt, Niamh Keane, Courtney J. Hillukka, Zachary J. Hammond, Julia E. Wiedmeier, Seth J. Welsh, Shulan Tian, Huihuang Yan, Ranjan Maity, Nizar Bahlis, Paola Neri, W Michael Kuehl, Marta Chesi, P Leif Bergsagel. IMiDs and BET inhibitors target distinct pathways of MYC dysregulation by super-enhancers in multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3015.